Define anonymous function in php
IntroductionAnonymous function is a function without any user defined name. Such a function is also called closure or lambda function. Sometimes, you may want a function for one time use. Closure is an anonymous function which closes over the environment in which it is defined. You need to specify use keyword in it.Most common use of anonymous function to create an inline callback function. Show
Syntax$var=function ($arg1, $arg2) { return $val; };
Anonymous function exampleExampleLive Demo OutputThis will produce following result. − cube of 3 = 27 Anonymous function as callbackIn following example, an anonymous function is used as argument for a built-in usort() function. The usort() function sorts a given array using a comparison function ExampleLive Demo $y; }); foreach ($arr as $x){ echo $x . "\n"; } ?> OutputThis will produce following result. − 3 10 21 54 70 Anonymous function as closureClosure is also an anonymous function that can access variables outside its scope with the help of use keyword ExampleLive Demo OutputThis will produce following result. − marks=285 percentage=95
Updated on 18-Sep-2020 13:35:13
Summary: in this tutorial, you will learn about PHP anonymous functions and how to use them effectively. Introduction to anonymous functionsWhen you define a function, you specify a name for it. Later, you can call the function by its name. For example, to define a function that multiplies two numbers, you can do it as follows:
The
In this example, the Besides named functions, PHP allows you to define anonymous functions. An anonymous function is a function that doesn’t have a name. The following example defines an anonymous function that multiplies two numbers:
Since the function doesn’t have a name, you need to end it with a semicolon ( This anonymous function is not useful at all because you cannot use it like a named function. To use an anonymous function, you need to assign it to a variable and call the function via the variable. The following example assigns the anonymous function to the
And this calls the anonymous function via the
When you dump the information of the
Note that the Since an anonymous function is an object, you can assign it to a variable, pass it to a function, and return it from a function. Passing an anonymous function to another functionPHP has many built-in functions that accept a callback function, for example, the
The The following example shows how to double each number in an array:
How it works.
Output:
This example works perfectly fine. However, it’s quite verbose. And the The following example does the same but uses an anonymous function instead:
Scope of the anonymous functionBy default, an anonymous function cannot access the variables from its parent scope. For example:
PHP issued the following notice:
In this example, the anonymous function attempts to access the To use the variables from the parent scope inside an
anonymous function, you place the variables in the
Now, it should work correctly. Note that the
In this example, inside the anonymous function the value of the If you want to pass a variable to an anonymous function by reference, you need to use the
Now, you see the Return an anonymous function from a functionThe following example illustrates how to return an anonymous function from a function:
How it works.
Summary
Did you find this tutorial useful? What is a anonymous function in PHP?Anonymous function is a function without any user defined name. Such a function is also called closure or lambda function. Sometimes, you may want a function for one time use. Closure is an anonymous function which closes over the environment in which it is defined. You need to specify use keyword in it.
How do you define an anonymous function?An anonymous function is a function that is not stored in a program file, but is associated with a variable whose data type is function_handle . Anonymous functions can accept multiple inputs and return one output. They can contain only a single executable statement.
What is anonymous function explain with example?In Python, an anonymous function is a function that is defined without a name. While normal functions are defined using the def keyword in Python, anonymous functions are defined using the lambda keyword. Hence, anonymous functions are also called lambda functions.
Where is anonymous function used?An anonymous function is not accessible after its initial creation, it can only be accessed by a variable it is stored in as a function as a value. 3. This function is useful for all scenarios. An anonymous function can be useful for creating IIFE(Immediately Invoked Function Expression).
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